Salvelinus namaycush 
System : Terrestrial
Kingdom
Phylum
Class
Order
Family
Animalia
Chordata
Actinopterygii
Salmoniformes
Salmonidae
- General
- Distribution
- Impact
- Management
- Bibliography
- Contact
Common name
Synonym
Cristivomer namaycush , (Walbaum, 1792)
Cristovomer namayacush , (Walbaum, 1792)
Salmo amethystinus , (Mitchill, 1818
Salmo amethystus , (Mitchill, 1818
Salmo confinis , (DeKay, 1842)
Salmo ferox , (Perley, 1852)
Salmo namaycush , (Walbaum, 1792)
Salmo pallidus , (Rafinesque, 1817)
Salvelinus namaycush , (Walbaum, 1792)
Cristovomer namayacush , (Walbaum, 1792)
Salmo amethystinus , (Mitchill, 1818
Salmo amethystus , (Mitchill, 1818
Salmo confinis , (DeKay, 1842)
Salmo ferox , (Perley, 1852)
Salmo namaycush , (Walbaum, 1792)
Salmo pallidus , (Rafinesque, 1817)
Salvelinus namaycush , (Walbaum, 1792)
Similar species
Salvelinus fontinalis
Summary
Salvelinus namaycush is a freshwater fish of the trout family, found primarily in lakes and large rivers worldwide. The distribution is broad due to the sport fishing industry and the demand for Salvelinus namaycush. In many of the introduced locations Salvelinus namaycush is an invasive species and reduces native biodiversity through competition and predation of endemic species. There have been some successful attempts to control Salvelinus namaycush using gillnetting and trapping.
Species Description
Cream coloured spots are found on the head and body, as well as the dorsal and caudal fins of Salvelinus namaycush. The average weight of S. namaycush is about 3 kg, but individuals will grow to up 27 kg if long lived. Average length of S. namaycush varies from 45 to 68 cm. The body is a slate grey to greenish with a lighter underside and a deeply forked caudal fin. Fins lower on the body are orange-red with a white edge. Breeding males will develop a dark stripe on their sides temporarily (Lenart, 2001).
Notes
Salvelinus namaycush are particularly susceptible to pollution, including but not limited to insecticides (FishBase, 2008). Hybrid crosses between female S. namaycush and male Salvelinus fontinalis called splakes, have been introduced into many areas of North America because of their ability to grow very quickly (Nova Scotia Fisheries and Aquaculture, Inland Fisheries Division. 2007).
Lifecycle Stages
Egg development for Salvelinus namaycush, depending on temperature, takes between 15 and 21 weeks to reach hatching which occurs between mid-February and late March (FishBase, 2008). The fry do not emerge from the crevices until a month after \"hatching\" in order to give time for the yolk sacs to absorb. The juveniles then fill their swim bladders near the surface and descend to deeper water where they remain for two or three years, which may be survival related since adults are found higher up in the water column and are known to be cannibalistic (Nova Scotia Fisheries and Aquaculture, Inland Fisheries Division, 2007).
Uses
Salvelinus namaycush was an important commercial fish stock in the US Great Lakes in the 1950's, but has since gone on the decline due to predation factors from sea lamprey. S. Namaycush remains a valuable sport fish for anglers worldwide (Lenart, 2001).
Habitat Description
Residing exclusively in freshwater, Salvelinus namaycush is found in lakes and rivers of varying sizes. The ability of S. namaycush to inhabit almost benthic-like environments gives it an upper hand in competition with other fish species. Within the water column, S. namaycush is found at both deep and shallow depths depending on the location and time of year as well as stage of development. S. namaycush prefers temperatures below 13°C and is rarely found in lakes with pH less than 5.2 (NatureServe, 2008)
Reproduction
Like many other aquatic species, Salvelinus namaycush fertilizes eggs externally, but unlike other species do not construct a 'redd' or nest. The act of spawning occurs predominately at night; where males will approach a female, press against her sides and quiver. During this act the females' eggs fall into rocky outcroppings beneath her after being fertilized by the male. This act of courting is repeated until all the eggs of the female are released. Occasionally, up to seven males and three females may interact together in a single spawning act. Spawning for S. Namaycush occurs annually in the southern range while only occurring every other year in more northern limits (FishBase, 2008).
Nutrition
Feeding on organisms from freshwater sponges to plankton, Salvelinus namaycush predates on a variety of underwater life. Organisms such as crustaceans, insects, fish and even small mammals are part of the diet of S. namaycush. When in the juvenile state, S. namaycush feeds almost exclusively on invertebrates. It was discovered that individuals which feed primarily on plankton grow slower, mature earlier at smaller sizes, die sooner and attain a smaller maximum size than those who predominately eat fish (FishBase, 2008). In larger lakes, S. namaycush is predominately piscivorous, where as in a smaller lake with less fish forage potential the predominate diet consists of crustaceans and plankton (Nova Scotia Fisheries and Aquaculture, Inland Fisheries Division. 2007).
Pathway
Salvelinus namaycush is primarily bred and stocked for recreational fisheries worldwide (Fuller, 2007).
Principal source: FishBase, 2008. FishBase, 2001.Salvelinus namaycush Lake trout.
Fuller, 2007. Salvelinus namaycush. USGS Nonindigenous Aquatic Species Database, Gainesville, FL.
Compiler: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
Review: Pam Fuller USGS/BRD, Nonindigenous Aquatic Species Program. Florida Integrated Science Center. USA
Publication date: 2009-05-21
Recommended citation: Global Invasive Species Database (2024) Species profile: Salvelinus namaycush. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=1363 on 20-04-2024.
General Impacts
The introduction of the invasive trout species Salvelinus namaycush has had detrimental effects on native biodiversity worldwide. Many various species of fish are affected not only by competition but by predation as well (Fuller, 2007). In the United States many endemic species are at risk due to the presence of S. Namaycush (Ruzycki et al. 2001) including the rare Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) (Fuller, 2007).
Management Info
Preventative measures: The use of potentially invasive alien species for aquaculture and their accidental release/or escape can have negative impacts on native biodiversity and ecosystems. Hewitt et al, (2006) Alien Species in Aquaculture: Considerations for responsible use aims to first provide decision makers and managers with information on the existing international and regional regulations that address the use of alien species in aquaculture, either directly or indirectly; and three examples of national responses to this issue (Australia, New Zealand and Chile). The publication also provides recommendations for a ‘simple’ set of guidelines and principles for developing countries that can be applied at a regional or domestic level for the responsible management of Alien Species use in aquaculture development. These guidelines focus primarily on marine systems, however may equally be applied to freshwater.
Copp et al, (2005) Risk identification and assessment of non-native freshwater fishes presents a conceptual risk assessment approach for freshwater fish species that addresses the first two elements (hazard identification, hazard assessment) of the UK environmental risk strategy. The paper presents a few worked examples of assessments on species to facilitate discussion. The electronic Decision-support tools- Invasive-species identification tool kits that includes a freshwater and marine fish invasives scoring kit are made available on the Cefas (Centre for Environment, Fisheries & Aquaculture Science) page for free download (subject to Crown Copyright (2007-2008)).
Physical: Gillnetting and trapping were deemed the most suitable management techniques for the control of Salvelinus namaycush in Yellowstone Lake (Kaeding et al. 1996). Electrofishing has also been proven to be effective in managing populations of S. namaycush, and is done yearly in Yellowstone Lake (Greater Yellowstone Science Learning Center. 8 Jan 2008).
